[WebCrypto][Mac] Replace CCECCryptorGetKeyComponents with CCECCryptorExportKey for...

[WebCrypto][Mac] Replace CCECCryptorGetKeyComponents with CCECCryptorExportKey for exporting ECC JWKs
https://bugs.webkit.org/show_bug.cgi?id=175657
<rdar://problem/33797150>

Reviewed by Brent Fulgham.

Source/WebCore:

CCECCryptorGetKeyComponents returns components in unpadded formats. In some minor cases, the ECC components
do need padding. Therefore, we occasionally see some corrupted outputs in JWKs. To overcome that, this patch
replaces CCECCryptorGetKeyComponents with CCECCryptorExportKey which does padding all the time.

In the meantime, this patch also makes export* methods return OperationError if any error occur in the
underlying operations though very unlikely.

Test: crypto/subtle/ecdsa-generate-export-import-jwk-sign-verify.html

* crypto/algorithms/CryptoAlgorithmECDH.cpp:
(WebCore::CryptoAlgorithmECDH::exportKey):
* crypto/algorithms/CryptoAlgorithmECDSA.cpp:
(WebCore::CryptoAlgorithmECDSA::exportKey):
* crypto/gcrypt/CryptoKeyECGCrypt.cpp:
(WebCore::CryptoKeyEC::platformAddFieldElements const):
* crypto/keys/CryptoKeyEC.cpp:
(WebCore::CryptoKeyEC::exportRaw const):
(WebCore::CryptoKeyEC::exportJwk const):
(WebCore::CryptoKeyEC::exportSpki const):
(WebCore::CryptoKeyEC::exportPkcs8 const):
* crypto/keys/CryptoKeyEC.h:
* crypto/mac/CryptoKeyECMac.cpp:
(WebCore::CryptoKeyEC::platformExportRaw const):
(WebCore::CryptoKeyEC::platformAddFieldElements const):
(WebCore::CryptoKeyEC::platformExportSpki const):
(WebCore::CryptoKeyEC::platformExportPkcs8 const):

LayoutTests:

* crypto/subtle/ecdsa-generate-export-import-jwk-sign-verify-expected.txt: Added.
* crypto/subtle/ecdsa-generate-export-import-jwk-sign-verify.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@220933 268f45cc-cd09-0410-ab3c-d52691b4dbfc